Should I change to a two stage pump?

[bx24]

Ok folks, fire away with your opinions ....

I have a 13hp Honda horizontal shaft engine and a 8 gpm pump. I have scavenged these parts so far for next to nothing and I am building a hydraulic power pack to run a log splitter and other hydraulic chores.

Here is my question. The 8 gpm should work fine for the splitter, but I like the idea of having quicker cycle times that a two stage pump can deliver. The one limiting factor is that the hoses I intend to use are 1/2".

Should I switch to a pump like this:

Haldex Hydraulic Pump — 22 GPM, 2-Stage, Model# 1080035 | Pumps | Northern Tool + Equipment

Or possibly this:

Haldex Hydraulic Pump — 28 GPM, 2-Stage, Model# 1080036 | Pumps | Northern Tool + Equipment

The motor should run the first one fine and with the right adjustments on the 2nd stage cutoff valve, the larger one would work as well. The only issue I see (besides spending money ... but hopefully eBay should get the prices down a bit), is that these pumps have 1" outputs which somewhat will comprimise their benifits.

My dilema is that while more faster would be good, there are are drawbacks as well:

1- When splitting logs, the 8 gpm should move things along and with the detent valve, I don't have to stay next to the splitter when it returns its cycle

2- What I have now paid for so that solution is free

3- As mentioned, the 1" output will be restricted by 1/2" hoses

4- On the plus side, the wood I usually get splits pretty easy so it may not even kick in the low gear side of the pump that much and that would be worth the price given the time savings.

Let me know what you think. The concern I would have about the 22 gpm pump is that it only puts out 3.5 gpm in "low gear" and my current pump puts out 8 gpm. FYI - the splitter that this will be used with (when I am splitting wood) uses a 4-way splitter with a 4x24 ram.

 

[bx24]

I just saw this one on eBay

Haldex Hydraulic Pump — 16 GPM, 2-Stage, Model# 1001507 - (eBay item 280176307493 end time Nov-28-07 19:47:25 PST)

16 / 3.5 gpm and both the shaft size and the output is 1/2" which would simplify things. So if that were the choice .... 8 gpm @ 2000 psi or 16 / 4-5 gpm if I pushed up the pressure on the low side of the pump (I am thinking the 13hp engine should be able to max out the adjustment given that this pump shows a minimum of 8hp)

 

[bx24]

Sorry, I was brain dead on the 2nd post. What I was thinking was that I could increase the adjustment so that it would not kick into low gear until a higher psi hits. So I would not incease the low end gpm, only prolong the time it takes to hits low gear

 

[Wayne County Hose]

Your 13 hp motor will run the 22 gpm no problem. Too small a motor for a 28 gpm.

I wouldn't worry about your output hose size. Most pumps I have seen this size are 3/4" outlet and then the log splitter manufacturer drops dowm to 1/2" hose anyway.

Your last concern, about your current pump doing 8 gpm and the new one 3.5 gpm on the 2nd stage, don't worry about it. The 22 gpm will get you to the log almost 3X quicker anyway. And, I believe that your 8 gpm pump will only put out 2000 psi anyway which will mean way less splitting power. The 8 gpm pump will not work with a 4 way wedge unless you are splitting balsa wood. They drop the 2 stage down to 3.5 gpm at high pressure for a good reason. Same pump shaft input speed, higher pressure, you have to drop the flow down. You will never get 8 gpm and 3000 psi out of the pump you have now with the 13 hp motor.

*The above are strictly my opinions and may be considered the ramblings of an idiot.*

 

[xlr82v2]

bx24,

What size cylinder do you have? I'd say that even with a 5" cylinder, the 22 gpm pump will give a plenty fast cycle time... With your 13hp engine, power is basicly not an issue... (5hp with 11gpm and a 4" cylinder is enough power to split 99.44%+ of anything a mortal man can wrestle up to the machine.) I'd stay away from the 28gpm pump... that would be crazy fast... almost unsafe fast. You may not have enough engine for the 28gpm either... hopefully Wayne County Hose will chime in... he's a hydraulics guru, he could tell if it would be enough grunt or not for that pump.

With a 4" cylinder on most splitters, 11gpm yields approximately a 14 second cycle time, so with a 22gpm pump and a 4" cylinder you're looking at a 7 second cycle time, and slightly slower with a 5" cylinder-without doing any math, I'd venture to guess the 5" would put you back in the 9 to 11 second range. I looked at the specs of a splitter with 16gpm (8hp) and a 5" cylinder, and it lists the cycle time at 15 seconds (all of these times are with 24" stroke cylinders).

So, with 13hp and 22gpm, you're going to be pretty fast no matter what size cylinder you have. You're getting up into the range where cooling may become an issue... so make sure you have plenty of capacity in your reservoir.

Let's see some pics when you get it built! Are you going vertical/horizontal or just horizontal? If horizontal only, wedge-on-beam or wedge-on-cylinder? I've got a lot of experience with both types (my dad has wedge-on-on beam, I've got wedge-on-cylinder, I much prefer the wedge-on-cylinder.)

 

[xlr82v2]

Don't ya hate it when you have to walk away right in the middle of making a post... only to come back and finish it, and then after it's up, you see that the guy you were hoping would chime in already did!

And also, you see the answer to your very first question in the very last line of the OP...

 

[Wayne County Hose]

bx24,

What size cylinder do you have? I'd say that even with a 5" cylinder, the 22 gpm pump will give a plenty fast cycle time... With your 13hp engine, power is basicly not an issue... (5hp with 11gpm and a 4" cylinder is enough power to split 99.44%+ of anything a mortal man can wrestle up to the machine.) I'd stay away from the 28gpm pump... that would be crazy fast... almost unsafe fast. You may not have enough engine for the 28gpm either... hopefully Wayne County Hose will chime in... he's a hydraulics guru, he could tell if it would be enough grunt or not for that pump.

With a 4" cylinder on most splitters, 11gpm yields approximately a 14 second cycle time, so with a 22gpm pump and a 4" cylinder you're looking at a 7 second cycle time, and slightly slower with a 5" cylinder-without doing any math, I'd venture to guess the 5" would put you back in the 9 to 11 second range. I looked at the specs of a splitter with 16gpm (8hp) and a 5" cylinder, and it lists the cycle time at 15 seconds (all of these times are with 24" stroke cylinders).

Brian, thanks for the kind words, but I am no hydraulic guru. Look at post # 4, last line. I do have some hydraulic knowledge, but it is kind of limited to certain applications.

Just remember that these pumps are rated in lab conditions. They don't take flow thru a valve or the rest of the hydraulic circuit into consideration. A 22 gpm pump will not be twice as fast as an 11 gpm pump in the same circuit. I like the trade off of speed for power in a larger bore cylinder. You don't lose as much speed as you gain power.

 

[bx24]

So the consensus seems to be that I should in fact go for the two stage pump (thanks).

Given that fact, now we can talk dollars. Does it make sense to go with the 16 gpm version for about $140 or the 22 gpm version for double that?

The cheap skate in me is starting to kick in and lean towards the 16 gpm (unless I will love the 22 gpm that much more) .....

Decisions ..... Decisions

 

[xlr82v2]

If the 22gpm version is double the price, then I for sure would go with the 16gpm. 16gpm with a 4" cylinder is going to have a pretty quick cycle time. I just looked on the Iron & Oak website (Brave Products' commercial division) and they've got a splitter with 16gpm pump and a 3.5" cylinder, and they're rating it at 8 seconds cycle time, so with a 4" cylinder I would guess your cycle time is going to be in the 10-11 sec range with a 16gpm pump.

 

[Wayne County Hose]

It really depends on the bore of your cylinder and how happy you want to be with it. If you have a 4" bore cylinder, go with the 16 gpm. 5" bore, you will be happier with the 22 gpm. You stated earlier that most of your wood splits quite easily, then do the 16 gpm pump with the 4" bore cylinder.

For the record, my splitter has a 5hp motor, 9 gpm 2 stage pump, and a 4" bore cylinder. It is plenty fast enough for me and splits absolutely anything I can put in it. I am happy with mine Yours with a 16 gpm pump and a 13hp engine and a 4" bore cylinder would be very fast and plenty powerful.